[Shifter]

Gotta hand it to the BBC though. All that mental gymnastics to come up with that word salad. Sci fi shows should hire them as writers when they need to come up with techno babble to suspend the audience disbelief

[stevecanuck]

@stevecanuck

Same question for you then - if the boat was in fact beyond the visible horizon when this was taken, how would that alter your conception / diagrams?

Nobody said the boat was beyond the visible horizon. At least I certainly didn't. Just the fact that we can see the boat means it's NOT beyond the visible horizon. Btw, I offered no diagrams.

[Tumeni]

... if the boat was in fact beyond the visible horizon when this was taken

For clarification/discussion of how you define 'visible horizon';



There are four boats/ships in this picture. One container ship and a smaller craft to the left, the double-craned ship to the right, and one in the far distance within the green circle. Here's a crop/zoom of that one.



I would suggest the 'visible horizon' is as indicated by my text in the first photo, with the green lines. Agree?

I would also suggest that three of the boats/ships are nearer than the horizon, and that only one, the one in the circle, is 'on the horizon'. Agree?

[jack44556677]

Nobody said the boat was beyond the visible horizon.

That's true.  It was just a hypothetical question.

Just the fact that we can see the boat means it's NOT beyond the visible horizon.

Not exactly.  There are examples of things that are beyond the visible horizon becoming visible when the conditions are right.

The idea that the ghostly horizon is the real one and the distinct/clear horizon is a "false" one is not typically how this illusion is understood.

[jack44556677]

I would suggest the 'visible horizon' is as indicated by my text in the first photo, with the green lines. Agree?

Certainly. The horizon is where the sky and surface (water in this case) appear to meet.  By "beyond the visible horizon", I mean the distant object (or some part of it) is no longer visible and appears to be "behind" the horizon.

I would also suggest that three of the boats/ships are nearer than the horizon, and that only one, the one in the circle, is 'on the horizon'. Agree?

Sure.

[Tumeni]

OK, my elevation, and hence my camera's elevation, was, give or take, 100m above sea level.

The ship with the two cranes is around 50m to the tops of the cranes. Estimating the height from the length/height proportions in the photo, based on the publicly-stated length, yields 44m, but other sources say 58m. In both cases, this is around half of the observer height. (44/100 or 58/100)

Do you agree that the sightline from 100m to the top of a 58m or 44m ship is a downward sightline?

Like Rowbottom's experiment; if he sighted along the flags, his sightline is level, he would look up to the higher flag at D, and look down to the black flag in the middle. Agree?

[SimonC]

Apart from the BBC explanation (much repeated elsewhere) you might find the local explanation interesting:–

https://www.cornwalllive.com/news/cornwall-news/ship-floating-clouds-cornwall-leaves-5070329

And I'll tell you a secret – the BBC don't get it right every time! You may remember another small mistake by a well-known BBC meteorologist: you might call it the Fish Effect.

You might also have seen another similar report from a Scot in recent days, with a similar explanation:–


Coincidentally the Cornish ship and the Scottish ship are very very similar. Same ship perhaps? Nessie springs to mind.